| Description |
Infrared and resonant two-photon ionization spectroscopy were employed to study the bonding and electronic structure of small gas phase transition metal containing molecules. Rovibrational spectra of NiCO, Ni(CO)3(13CO), and Ni(CO)3(C18O) were collected using a pulsed-discharge slit-jet infrared diode laser spectrometer, while resonant two-photon ionization spectra were collected for ZrF, ZrCl, and PdSi. Analysis of these spectra allowed spectroscopic parameters to be determined, leading to an improved understanding of the chemical bonding in these molecules. Spectra of NiCO, Ni(CO)3(13CO), and Ni(CO)3(C18O) were obtained by exciting a CO vibration in these molecules. For NiCO, band origins of 2010.69289(34) and 2010.64528(23) cm-1 were measured, along with values of B0 = 0.151094(7) and 0.149597(6) cm-1 for 58NiCO and 60NiCO, respectively. These were used to determine bond lengths of r0 (Ni-C) = 1.641(40) A and r0 (C-O) = 1.193(53) A. The ground state constants determined for Ni(CO)3(13CO) are υ0 = 2022.075753(95) cm-1 and B" = 0.034736(2) cm-1. For Ni(CO)3(C18O), υ0 = 2021.93683(18) cm-1 and B" = 0.033764(4) cm-1 are obtained. These values provide bond lengths of r0(Ni-C) = 1.839 ± 0.007 A and r0(C-O) = 1.121 ± 0.010 A. The vibronic spectrum of ZrF revealed many bands in the range from 14700 to 18000 cm-1, several of which can be grouped into three band systems. Rotationally resolved investigations are hampered by perturbations in the excited states, but three unperturbed bands have revealed an Ω″ = 1.5 ground state, and a bond length of r0″ = 1.858 A. Hot bands originating from v″ = 1 provide ΔG1/2″ = 691.45(2) for 90Zr19F. Based on comparisons to ZrCl and ligand-field considerations, the ZrF ground state is assigned as a 2Δ3/2. In addition to the ZrF measurements, vibronically resolved spectra of ZrCl were recorded over the 13000 to 18000 cm-1 range, and four band systems were identified. Three vibronic bands of PdSi have been rotationally resolved and analyzed, two of which are perturbed by interactions with other states. The data show an Ω = 0 ground state and a bond length of r0″ = 2.0824(3) A. Comparisons to density functional (DFT) calculations strongly support a 1Σ+ ground state assignment. |
